Constructions for reed relay protection switch-up adjustment on the 110-220 kV wireways.

Zhantlessova A.B., Kletsel M.J., Polischuk V.I.

Reed relay based devices, a  magnetically operated contacts ( MOC ) [ 1-4 ] without current transformer, can provide a way to save a resources such steel and copper on the protective relaying  ( PR ) of  the electric power systems. This report is related to reed relay mounting constructions and adjustments on the elements of  the  110-220 kV electric power system with horizontal or triangular  configuration of the wireways

The construction for 110 kV triphase symmetrical wireways (Fig. 1a) allow us to control the protection pickup current  [5] by changing the position of reed relay according to the conductor over the bar 1  using the bolts  2 , as well as inside the case using the handle (Fig. 1)

                      à                                                                  á

Figure 1- Reed relays mounted on the triphase symmetrical support: a) 110 kV wireway; b) 35 kV wireway

 

The clip 6 (Fig. 1a) holds the plate 5 which fixing an equilateral triangle shaped support 7 and base with reed relays by the mounting bolts 9. On the fig. 3 it can be seen that the position of the reed relay inside the casing can be fixed by the stud 11 and the casing 16 is fixed on the plate 9 by the tie-down lug 10. The platform 14  is settled in the required position using the screwed shank 13 with handle 12. The quantitative assessment of the angle variation is displayed in aperture 16 on the upper side of the casing 16.

Demonstrated construction allows the reed relay to be moved in horizontal and vertical planes. At the same time the angle between horizontal plane and axis of elongation of reed relay can be settled without removing of the case cover, so device maintenance is simplified. The protection pickup current  can be selected as shown in [5].

A construction [6] for the 6-35 kV electric power installations  includes  bars 1 with holes 2 (Fig. 1 b), bolts with thumb-nuts 3, attaching bolts 4, plates with reed relays mounted 5 and split casings 6 with the reed relay position changing devise similar to the casing for 35- 110 kV construction (Fig. 2).

The position of the plate 5 can be changed along the scaled rod 1 with a scale. The rods are attached to the sides of an equilateral triangle shaped construction by two mounting bolts 4. Moving the reed relay on the plate to the left or to the right according to the conductor can be done by using the adapter (Fig. 2). The position of reed relays on the remaining plates can be regulated similarly.

 

Figure 2 – The adapter

 

The design for 220 kV three-phase high-voltage power line with asymmetrical conductors (Fig. 3), similar to the previous constructions contains plate 1(6) attached to the tower by two clips 2, or two clips and  wire rope 3. The reed relay position adapter  4 (Fig. 3) is mounted on the plate by the clamp locks 5(7) . This allows us  to arrange the reed relay  between  the A and C phases, as same as  between  the B and C phases.

The protective relaying construction of 220 kV three-phase high-voltage power lines with asymmetrical conductors  and single-circuit suspension towers is rigidly fixed on the tower, which reduces errors in determination of protection pick-up current.

In accordance with the law of Bio - Savart - Laplace, the field density (FD) , created by the phase currents ,  è , and acting at the point M along the axis of elongation  of the reed relay (RR) [5] is :

                (1)

where  ( and  ) is a FD at the point M created by  the current  ( and );  ( and ) is the angle between the axis of elongation of the RR and  ( and ); and  is the magnetic permeability of air.

To the RR-1 acted as a filter of zero-sequence current , it must respond to . As seen from (1), it is possible if:

                                      (2)

When substituting positive-sequence current , , in (1) instead of the currents , , respectively, under conditions (2), we find that field density  created by them is equal to zero, that is, these currents do not affect the RR-1. Similarly, it is correct for the negative sequence currents as well. By substituting in (1) zero-sequence currents , ,  instead of , , ,   we get . Hence, there is only magnetic field produced by currents  is affecting the RR-1, and the problem reduces to determining the coordinates of the reed relay, in which condition (2) is satisfied.

Figure 4 – design for 220 kV high-voltage power line

 

In [2] it is shown that position of  the reed relay,  performing the duty of  the filter of zero-sequence current, must be on a circle of radius R, circumscribed around a triangle connecting the points A, B, C, and the axis of elongation of the reed relay should coincide with the tangent of the circle.

Conclusions: Four formations of reed relay protection switch-up adjustment are developed for the 110-220 kV electric power installations with a horizontal and a triangular configuration of the wireways. Common to all is a reed relay position adapter, disposed inside the casing, and a distinguishing feature are  the  different ways of mounting the plates with platforms for the reed relays.  .

REFERENCES

1.  Kletsel M.J., Musin V.V. The reed relay based constructions for protection of the high voltage installations without the current transformers//Electrical Engineering.1987. ¹ 4. Pp. 11-13.

2.  Zhalmagambetova U. C., Zhantlessova A.B., Kletsel M.J., Mayshev P.N. The reed relay as a filter of zero-sequence current. / / Scientific problems of transport in Siberia and the Far East. , 2011.  ¹ 1, Novosibirsk, Pp 300-303.

3. Zhulamanov M.A., Kletsel M. J. reed relay based resistance relay// Electrical Engineering. - 2004. - ¹ 5. - P.38 - 44

4. Kletsel M.J., Mayshev P.N. Features of reed relay based constructions for phase differential protection of current transformers. / / Electrical Engineering. - 2007. - ¹ 12. - Pp. 2 - 7.

5.Preparatory patent ¹ 19882 of the Republic of Kazakhstan. Measuring element for relay protection of 35 ÷ 110 kV triphase symmetrical wireways // Kletsel M.J., Zhantlessova A.B., Zhantlessova B.B., Mayshev P.N. Publ. 8/15/2008, Bull. ¹ 8.

6.Preparatory  patent ¹ 19636 of the Republic of Kazakhstan. Measuring element for relay protection of 6-35 kV triphase symmetrical wireways // Kletsel M.J., Zhantlessova A.B., Zhantlesova B.B.Publ. 31/07/2006.